This is a transcript of a home-made sheet of ISO Transport protocol Decodes I prepared when decoding ISO Transport Protocol was a daily occupation. This was not recently :-) Putting it here allows me to throw the page away from my diary and might be of some interest. Check against the standard before you believe it.
| Name | Type | Valid Classes |
Max Length |
Parameters | Max User Data | |
|---|---|---|---|---|---|---|
| Connect Request | CR | All | 128 | C0-C7, 85-89, 8B | 33 octets, not class 0 or 1 | |
| Connect Confirm | CC | All | undef | C0-C7, 85-89 | 33 octets, not class 0 or 1 | |
| Disconnect Request | DR | All | 128 or TPDU size |
E0, C3 | 65 octets, not class 0 or 1 | |
| Disconnect Confirm | DC | not 0 | undef | C3 | none | |
| Data | DT | All | TPDU size | C3 | TSDU | |
| Expedited Data | ED | NF | undef | C3 | exp TSDU (1-16 octets) | |
| Acknowledge | AK | NC | undef | C3, 8A, 8C | none | |
| Expedited Ack | EA | NF | undef | C3 | none | |
| Reject | RJ | 1,3 | undef | none | none | |
| Error | ER | All | undef | C3, A1 | none |
NF: not class 0, not class 2 when non-explicit flow-control selected.
NC: as NF plus not class 1 when receipt confirmation selected.
The following codes are used:
Parameters appear as TLD (Type-Length-Data) triples.
| Code | Name | Classes | Length | Value |
|---|---|---|---|---|
| 85 | Ack Time | 4 | 2 | binary integer: max ack time in ms |
| 86 | Resid. error rate | not 0 | 3 | oct 1: target as power of 10; oct 2: min acceptable as power of 10; oct 3: TSDU size as power of 2 |
| 87 | Prority | not 0 | 2 | Integer, 0 is highest |
| 88 | Transit delay | not 0 | 8 | oct 1&2: target calling-called oct 3&4: max acceptable calling-called oct 5&6: target called-calling oct 7&8: max acceptable called-calling |
| 89 | Throughput | not 0 | 12 or 24 | oct 1-12: max throughput; oct 13-24: av throughput (optional) 1st 3 oct: target calling-called 2nd 3 oct: min acceptable calling-called 3rd 3 oct: target called-calling 4th 3 oct: min acceptable called-calling |
| 8A | Subsequence Num | 4 | 2 | sub-sequnce num for AK TPDUs |
| 8B | Ressign Time | 1 or 3 | 2 | TTR time in seconds in binary |
| 8C | Flow Control Conf | 4 | 8 | if b8 oct 1=1 next 31b are YR-TPDU-NR from rcd AK TPDU, next 16b sub-seq param of rcd AK TPDU, last 16b your credit. Normal form: final bits of each field significant |
| A1 | Invalid TPDU | All | undef | bit pattern of RJ'd TPDU up to and including octet causing RJ |
| C0 | TPDU size | All | 1 | max TPDU as 2^value default 07 (128 octets) |
| C1 | Calling TSAP | All | undef | id |
| C2 | Called TSAP | All | undef | id |
| C3 | Checksum | 4 | 2 | Checksum |
| C4 | Version | not 0 | 1 | 01 |
| C5 | Security | not 0 | undef | undef |
| C6 | Additional Option | not 0 | 1 | default 01 b4=1 use network exp in class 1 else not b3=1 use rcpt confirm in class 1 else not b2=1 do not use checksums in class 4 b1=1 use transport expedited. b8-b5 0. |
| C7 | Alt. protocol class | not 0 | n | seq of single octets for alt prot classes |
| E0 | Disconnect info | All | undef | user-defined |
These are examples from real connections, so might or might not be valid!
14D00089005D40C202D9C5C0010AC60103850205D0 is a CC with parameters for Called TSAP, TPDU Size, Additional Options, Ack Time
0680006D009800 is a DR with no reason specified